18 Argon


atomic number 18
atomic mass 20
number of protons 18
number of neutrons 22
number of electrons 18
period group 18
melting point -189.2
boiling point -185.8
state (solid, liquid, gas) gas
density 1.784 g/L
metal or non metal metal
colour of element colourless

external image bohr_atom.gif
who discovered it William Ramsay, Baron Rayleigh
when was it discovered 1894
where was it discovered Scottland
flammable inert gas ( doesn't react) non flammable
interesting facts in earths atmisphere argon is the third most common used gas.